Method of making sulphurized



Patented Apr. 23, 1940 UNITED S ATES PATENT orrics METHOD or MAKING SULPHURIZE CUTTING OILS Arthur Pollak and Randall Hastings, New York,

. N. Y., assignors to West Virginia Pulp and Paper Company, New York, N. Y., a corporation of Delaware No Drawing. Application April 27, 1939,

Serial No.

1 Claim.

Our present invention relates to an improved method of making a sulphurized cutting oil. Cutting oils as at present used are of two kinds: (1) the oil is emulsified with water and the emulsion used for cooling and lubricating. the

metal during the cutting operation; (2) the oil;

and rosin acids occurring in pine and other nondeciduous woods, and is obtained as a by-product in paper manufacture. In some instances the crude tall oil is purified by distillation and K separation of the rosin acids by crystallization.

Tall oil, especially the refined variety, is capable of absorbing in excess of 25% by weight of sulphur. The sulphurized tall oil is then as a rule diluted with other oils having lubricating quali- 25 ties, either vegetable or mineral or both (previously saturated with sulphur), the sulphurretaining capacity. of which is substantially less than that of the tall oil.

Difliculty has been experienced in maintaining an the quality of such cutting oils, as ordinarily the sulphurized oil deposits a sludge upon standing which detracts from the usefulness of the oil for cutting purposes. We have now discovered that this deposition of sludge may be reduced to a. ragpoint where such sludge is no longer objectionable. In general our method consists in heating the tall oil and sulphur in admixture therewith under controlled conditions as to time and temperature. For the best understanding of our 49 inveptionreterence is made to the following specific example illustrative thereof: 400 grams or refined tall oil is placedin a flask provided with a thermometer, the flask atc-tached to a stirrer and placed in a vat of trias cresyl phosphate heated by a Bunsen burner. 80 grams (20%) of powdered sulphur is added and the heating continued with agitation until a temperature of 350? I". is reached. Alter maintaining'the temperature at this value for two hours c a clear solutionjs obtained upon cooling.- When sulphurized tall oil so prepared was diluted with a mineral cutting oil nine times its weight the solution remainedclear. A sample oi the oil so obtained was kept at 200 F. for ten'days and iound to yield only 0.64% sludge.

In general the following conditions are to be, observed: The sulphur should be heated with tall oil until such time as a test sample when cooled shows no deposition of sulphur, but in general for a timeless than four hours, after which appreciable decomposition of the oil results especially at the higher temperatures as evidenced by the evolution of hydrogen sulphide. The temperature, on the other hand, should not be substantially less than 300 F. nor substantially over 400 F. By observing these conditions, from to 30% of sulphur may be incorporated in the tall oil and a stable product obtained which may be diluted with a hydrocarbon or other cutting oil and such mixture used directly for cutting purposes or emulsified with water in known man ner. In general an optimum time and temperature within the limits above stated will be found for various amounts of sulphur. Thus, in a series of test runs the sludge deposition was found to result when using 15% sulphur at 350 F. temperature in three hours heating time; for

% sulphur, minimum deposition occurred with two hours heating time at the same temperature; with sulphur, minimum deposition was found 85 to result at 400 F. and two hours heating time, temperatures higher or lower, or different periods of heating giving' a greater' amount -of sludge. The sulphur present should go into solution before any substantial evolution of hydrogen sulphide occurs; should appreciable quantities of hydrogen sulphide be formed, the heating should be stopped and the mixture allowed to'cool and either decanted from the uhdissolved sulphur or filtered, since continued heating under these circumstances will result in destruction of the oil substance. v v

While preferably the tall 011 is first sulphurizedand then diluted with lubricating (cutting) oil, if desired the tall oil may be at least partly diluted prior to the sulphurizing operation. Other variations in the disclosed method will occur to,those skilled in the art within the scope of our invention.

We claim: 45

- In the method of making sulphurized cutting, oils by heating tall oil with agitation with up to byweight of sulphur in the temperature range 01' approximately 300-400 F., the step of. controlling the solution of the sulphur to give a minimum of sludging by terminating the heating within a period of from two to four hours, beyond which period a greater amount of sludge will be produced.

- ARTHUR POLLAK.

RANDALL memos. 

